Peer support is increasingly positioned as a scalable response to gaps in mental health care, particularly in digitally mediated settings, yet what counts as peer support and how responsibility is distributed remain unevenly defined in practice. Drawing on interviews with peer supporters, we show how lived experience, moral commitment, and self-identification shape participation while blurring expectations around scope, authority, and accountability. Institutional ambiguity concentrates emotional labour, boundary-setting, and escalation of responsibility at the individual level, often without consistent organisational scaffolding. Participants evaluated AI not primarily through empathy or technical capability, but through how technologies redistribute risk, labour, and accountability within already fragile support roles. Building on these findings, we outline design futures for an AI-supported peer support ecosystem that foregrounds responsibility as a central design concern rather than treating AI as a mechanism of scale.

翻译：同伴支持日益被视为应对精神卫生服务缺口的一种可扩展方案，尤其是在数字化媒介环境中。然而，在实践中，何为同伴支持以及责任如何分配，其定义仍然参差不齐。通过对同伴支持者的访谈，我们揭示了亲身经历、道德承诺与自我认同如何塑造参与行为，同时模糊了关于范围、权威与问责的预期。制度层面的模糊性使得情感劳动、边界设定与责任升级集中于个人层面，且往往缺乏一致的组织架构支撑。参与者对人工智能的评估并非主要基于共情或技术能力，而是着眼于技术如何在已然脆弱的支持角色中重新分配风险、劳动与问责。基于这些发现，我们勾勒出一个以人工智能为支撑的同伴支持生态系统设计未来，将责任作为核心设计关切，而非将人工智能仅视为规模化机制。